[Python-Dev] Is XML serialization output guaranteed to be bytewise identical forever? (original) (raw)

Terry Reedy tjreedy at udel.edu
Thu Mar 21 16:37:41 EDT 2019

On 3/21/2019 1:23 PM, Paul Moore wrote:

On Thu, 21 Mar 2019 at 17:05, Steve Holden <steve at holdenweb.com> wrote:

Especially as the standards specifically say that ordering has no semantic impact.

Byte-by-byte comparison of XML is almost always inappropriate. Conversely, if ordering has no semantic impact, there's no real justification for asking for the current order to be changed. In practice, allowing the user to control the ordering (by preserving input order) gives users a way of handling (according to the standard) broken consumers who ascribe semantic meaning to the attribute order.

Or, as Jonathan Goble said elsewhere, use an order that makes whatever sense to the author and other readers. The order of positional parameter names in a function definition has no semantic meaning to python, but it would be terrible to make them be sorted.

-- Terry Jan Reedy

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